DCFM Enterprise User Manual (53-1001775-01, June 2010)

380 DCFM Enterprise User Manual

53-1001775-01

FCIP Trunk configuration considerations

There are several points to consider when configuring an FCIP trunk:

• Each FCIP circuit is assigned a pair of IP addresses, one source IP address, and one

destination IP address.

• The source IP address is used to determine which GbE interface to use. The GbE IP address

must be on the same IP subnet as the source IP address. IP subnets cannot span across the

GbE interfaces.

• The destination IP address is used to determine routing. If the destination IP address is also on

the same subnet as the GbE interface, packets are routed over that subnet. If the destination

IP address is on a different subnet, traffic must be routed to an IP gateway address.

• An FCIP circuit can have a maximum commit rate of 1,000,000 Kbps.

• In a scenario where a FCIP tunnel has multiple circuits of different metrics the data will flow

over the lower metric circuits unless a failover condition occurs, as described in “FCIP circuit

failover capabilities”.

• The maximum bandwidth for a single circuit is 1 Gbps. To utilize the entire bandwidth of an

XGE (10GbE) port, you must create ten 1 Gbps circuits.

FCIP circuit failover capabilities

Each FCIP circuit is assigned a metric, which is used in managing failover for FC traffic. Typically,

the metric will be either 0 or 1. If a circuit fails, FCIP Trunking tries first to retransmit any pending

send traffic over another lowest metric circuit. In Figure 150, circuit 1 and circuit 2 are both lowest

metric circuits. Circuit 1 has failed, and transmission fails over to circuit 2, which has the same

metric. Traffic that was pending at the time of failure is retransmitted over circuit 2. In order

delivery is ensured by the receiving 7800 switch.

FIGURE 150 Link loss and retransmission over peer lowest metric circuit

7800

Circuit 1

Circuit 2

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